1. Field of the Invention
The present invention relates to the transmission of multicast and broadcast information between at least one mobile station and a controller of a wireless network.
2. Description of the Prior Art
Work to standardize multimedia broadcast multicast service (MBMS) as a new bearer to point to multipoint service has started in the third generation partnership project (3GPP). The aim of this work is to introduce new capabilities not only in Universal Terrestrial Radio Access Network (UTRAN) but also in the core network (CN) so as to provide point-to-multipoint services which use common network resources but which are intended to a restricted group of people (subscribers or users) in a cell. These requirements are not fully completed in the current cell broadcast concepts of 3GPP which is already standardized in 3GPP release 99 which is incorporated herein by reference in its entirety.
Even though standardization work in radio access network (RAN) working groups has not been fully started, some basic principles between RAN working groups and service architecture (SA) working groups have already been agreed. One such agreement includes that there is a no need for a retransmission functionality for multicast services which has been seen as not a feasible requirement from the UTRAN point of view. In practice, this means that the Radio Link Control layer (RLC) in UTRAN will support an unacknowledged mode (UM) or even transparent mode (TM) which does not require any previous information about the upper layer packet sizes which are used during the active multicast transmission of data through the air interface.
Another clear requirement from the UTRAN point of view is transmission of multicast related control and announcement information to and from the network to and from the mobile stations. In practice this means that, if transmission of control information is tied with the transmission of multicast data, i.e. through the same air physical channel, the multicast or broadcast concept used In UTRAN must be capable of separating the control information (i.e. control plane) and the multicast data (i.e. user plane) from each other. Due to the nature of multicast service transmission, when control information is sent to the air interface without knowledge regarding the current state of the authorized mobile stations, the control information (e.g. announcement frames) may have to be repeated without changing the content of the frame by changing the sequence number SN of the RLC Packet Data Unit (PDU). In this case, a comparison between an old and a new control frames cannot be made from the sequence number and therefore, something is required to recognize the reception of the already received control frames.
Broadcast and multicast transmissions are well-known. Broadcast transmissions are sent to mobile stations, whose identification and location are unknown as the result of, for example, no joining procedure having been completed. Multicast transmissions, on the other hand, are transmitted to only those subscribers that have previously indicated an interest in receiving the multicast services from the network, who can be identified after performance of the multicast joining procedure and/or whose location can be determined by tracking procedures.
In order to establish if subscribers or users, who control the mobile stations, are willing to receive a service providing a multicast or restricted broadcast transmission, two phases are executed. The first phase is the service registration phase during which subscribers or users, who possess the mobile stations, agree with the a service provider or operator, who controls the core network or the external network connected thereto, to receive the multicast or restricted broadcast services. The second phase is the multicast joining or subscription phase during which the subscribers or users, who possess the mobile stations, indicate a willingness to the service provider to receive the multicast or restricted broadcast services in order to obtain currently defined service configuration parameters of the multicast or restricted broadcast services. If the current service parameters have already been given to the mobile stations during the registration phase, the user of the mobile stations indicates a readiness to receive multicast or restricted broadcast services which enables the wireless network and the external network to make routing and resource management decisions which involve point to multipoint connections, such as a connection between the core network and the mobile stations regarding the offered service.
The most significant event of the above-described registration and multicast joining or subscription phase is the indication by the subscriber or user of the mobile stations of a willingness to receive an ordered multicast or restricted broadcast service from the service provider controlling the external network or network connected thereto. Subscription, which is required for the broadcast services (i.e. broadcast service, which are meant only to a restricted group of people), is always non-time critical (i.e. it can be made e.g. hours before the reception of the broadcast service, whereas the joining phase can be time critical (i.e., it is made just before the multicast transmission of the particular service is started) or a non-time critical transaction (i.e., the joining phase can be completed before the actual service activation). Depending on whether the joining transaction is a time-critical or a non-time critical transaction, services involving different subscriber service charges can be defined for the multicast or restricted broadcast service. This is a significant aspect of providing multicast or restricted broadcast services.
Currently, the 3GPP project has not specified a mechanism for separating multicast and broadcast related control plane (control information) from the user plane (user data).
The present invention provides a method and system which transmits control information and user data, relating to multicast or broadcast services, between a first information entity within at least one mobile station and a second information entity within a controller of a wireless network in which the at least one mobile station is located. The control information and user data is transmitted by using the same radio resources. Furthermore, the multicast and broadcast related control information and the user data may be transmitted during an active multicast or broadcast session. The mobile stations separate the already received control information from the first-time-received control information from each other. If the control information is such that it is repeated time after time, the mobile stations can decide to delete repeated packets at the RLC layer or whether to send the repeated packets to an upper layer. If the RLC sees that the packet is a duplicate of a previous one, the RLC layer can save the mobile station processing capacity and power by avoiding having to interpret the content of the packet.
Separation of the control information from the user data may be affected in any number of ways:
1. In one embodiment of the invention, the separation occurs at the RLC layer using two RLC entities and is made with two logical channels identified by corresponding values in Target Channel Type Field (TCTF) headers of data packets in the RLC layer. This embodiment does not require any changes to the existing PDU structure of the RLC and MAC layers in accordance with current standardization, such as 3GPP.
2. In a second embodiment of the invention the control information and the user data is also separated in the RLC layer using one RLC entity and two new logical channels. A length indicator is used in the header of the RLC layer to identify the type of logical channel to which the packets belong. No changes are required for the PDU structure in both the RLC and the MAC layers in accordance with current standardization such as 3GPP. This embodiment permits a RLC entity to send or generate control frames in an UM. In this way the same resources can be used for user and the control planes and now new RLC PDU structures or control devoted protocol layer is needed to identify.
3. In a third embodiment, a single logical channel is used between the MAC layer and a Multimedia Broadcast Multicast Center (MBMC) network layer. At the MAC layer, a TCTF field header identifies a type of logical channel to which the packet belongs. At the RLC layer, a length indicator header indicates the PDUs which contain control information. At the (MBMC) network layer, an indicator header identifies the type of control information contained in the packets (e.g. announcements).
A method of transmitting control information and user data, relating to multicast or broadcast services, between a first information entity within at least one mobile station and a second information service within a controller of a wireless network in which the at least one mobile station is located in accordance with the invention includes originating control information from at least one first information service entity; encoding the control information at the at least one mobile station on a logical channel; transmitting the logical channel on a physical channel from the at least one mobile station to the controller; decoding the physical and the logical channels at the controller and providing the control information to the second information entity; providing user data at the second information service entity; encoding the user data at the controller on a logical channel; encoding the logical channel, on which the user data is encoded, on a physical channel and wirelessly transmitting the physical channel on which the logical channel is encoded from the controller to the at least one mobile station; and decoding the physical channel and the logical channel on which the user data is encoded at the at least one mobile station and providing the user data to at least one of the first information entities. The multicast or broadcast services may be provided from another network to the second information entity; and the user data provided at the second information entity may be the multicast or broadcast services provided by the another network. The logical channel encoding the control information may be a first logical channel; and the logical channel encoding the user data may be a second logical channel. The logical channel on which the control information is encoded at the at least one mobile station and the logical channel which is decoded at the controller may be bi-directional. The at least one mobile station and the controller may have a protocol stack with a medium access control layer and radio link control layer with the medium access control layer including packets including a field identifying the logical channel on which the control information is encoded and the radio link control layer including packets including a field identifying a type of control information; and the fields may be used to process the control information and the user data. The at least one mobile station and the controller may have a protocol stack with a medium access control layer and radio link control layer with the medium access control layer using packets including a field identifying a type of logical channel containing the packets of the medium access control layer and the radio link control layer using packets including a field identifying a type of control information contained in packets of the radio link layer; and the fields may be used to process the control information and the user data. A protocol stack with a medium access control layer and a radio link control layer may be coupled to the medium access control layer by the logical channels with the logical channel encoding the control information being bi-directional and the logical channel encoding the user data being unidirectional. The radio link control layer may comprise first and second radio link control entities which respectively process the control information and the user data. The radio link control layer may comprise a single radio link control entity which processes the control information and the user data. A protocol stack may be provided with a network control layer, a medium access control layer coupled to the network control layer by a single logical channel and a radio link control layer coupled to the medium access control layer by a single logical channel; and wherein the medium access control layer may use packets including a field identifying a type of logical channel containing the packets of the medium access control layer, the radio link control layer may use packets including a field identifying control packets within the single channel and the network control layer may use packets including a field identifying a type of control information in the identified control packets; and wherein the fields may be used to process the control information and the user data. A first radio resource control entity may be coupled to one of the first information entities and to a radio link control layer of the at least one mobile station, which receives the control information from either the first information entity or to the radio link control layer of the one the at least one mobile station entity; and a second radio resource control entity, may be coupled to the second information service entity and to a radio link control layer of the controller, which transmits the control information to either the second information entity or to the radio link control layer of the controller. The control information may comprise multicast joining messages or broadcast subscription messages. The control information may comprise announcements of multicast services or broadcast services to be offered. The control information may command the at least one mobile station to periodically repeat an announcement of multicast or broadcast services.
A system which transmits control information and user data in accordance with the invention includes a wireless network including mobile stations and a controller; a first information entity in each mobile station; and a second information service entity in the controller; and wherein at least one first information entity originates control information; the originated control information is encoded by at least one mobile station on a logical channel; the at least one mobile station transmits to the controller the logical channel encoded on a physical channel; the controller decodes the physical and logical channels and provides the control information to the second information entity; user data is provided at the second information entity; the user data is encoded at the controller on a logical channel; the logical channel on which the user data is encoded is encoded on a physical channel and wirelessly transmitted with the physical channel on which the logical channel is encoded from the controller to the at least one mobile station; and the at least one mobile station decodes the physical channel and the logical channel on which the user data is encoded and provides the user data to at least one of the first information service entities. The multicast or broadcast services may be provided from another network to the second information entity; and the user data provided at the second information entity may be the multicast or broadcast services provided by the another network. The logical channel encoding the control information may be a first logical channel; and the logical channel encoding the user data may be a second logical channel. The logical channel on which the control information is encoded at the at least one mobile station and the logical channel which is decoded at the controller may be bi-directional. The at least one mobile station and the controller may have a protocol stack with a medium access control layer and radio link control layer with the medium access control layer including packets including a field identifying the logical channel on which the control information is encoded and the radio link control layer including packets including a field identifying a type of control information; and the fields may be used to process the control information and the user data. The at least one mobile station and the controller may have a protocol stack with a medium access control layer and radio link control layer with the medium access control layer using packets including a field identifying a type of logical channel containing the packets of the medium access control layer and the radio link control layer using packets including a field identifying a type of control information contained in packets of the radio link layer; and the fields may be used to process the control information and the user data. A protocol stack with a medium access control layer and a radio link control layer may be coupled to the medium access control layer by the logical channels with the logical channel encoding the control information being bi-directional and the logical channel encoding the user data being unidirectional. The radio link control layer may comprise first and second radio link control entities which respectively process the control information and the user data. The radio link control layer may comprise a single radio link control entity which processes the control information and the user data. A protocol stack may be provided with a network control layer, a medium access control layer coupled to the network control layer by a single logical channel and a radio link control layer coupled to the medium access control layer by a single logical channel; and wherein the medium access control layer may use packets including a field identifying a type of logical channel containing the packets of the medium access control layer, the radio link control layer may use packets including a field identifying control packets within the single channel and the network control layer may use packets including a field identifying a type of control information in the identified control packets; and wherein the fields may be used to process the control information and the user data. A first radio resource control entity may be coupled to one of the first information entities and to a radio link control layer of the at least one mobile station, which receives the control information from either the first information entity or to the radio link control layer of the one the at least one mobile station entity; and a second radio resource control entity, may be coupled to the second information service entity and to a radio link control layer of the controller, which transmits the control information to either the second information entity or to the radio link control layer of the controller. The control information may comprise multicast joining messages or broadcast subscription messages. The control information may comprise announcements of multicast services or broadcast services to be offered. The control information may command the at least one mobile station to periodically repeat an announcement of multicast or broadcast services.